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Дисертації з теми "Calcium and integrin binding protein"

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Автор: Grafiati
Опубліковано: 10 грудня 2022
Оновлено: 28 січня 2023

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1

Blamey, Chad Joseph. "Calcium- and integrin-binding protein 1 structure and function /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 3.06 Mb., p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:3220732.

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Анотація:
Thesis (Ph.D.)--University of Delaware, 2006.
Principal faculty advisors: Ulhas P. Naik, Dept. of Biological Sciences and Brian J. Bahnson, Dept. of Chemistry and Biochemistry. Includes bibliographical references.
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2

Maddox, Katherine. "A characterization of the calcium- and integrin-binding protein family." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 112 p, 2009. http://proquest.umi.com/pqdweb?did=1654487501&sid=7&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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3

Rousset, Céline. "Étude de l'interaction entre le domaine cytoplasmique de l'intégrine [alpha]IIb et la "calcium- and integrin-binding protein (CIB)"." Lille 1, 2002. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2002/50376-2002-331.pdf.

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Анотація:
La "calcium- and integrin-binding protein" (CIB) est une protéine cytoplasmique fixatrice de calcium, interagissant spécifiquement avec le domaine cytoplasmique de la sous-unité alpha de l'intégrine [alpha]IIb[bêta]3 (intégrine spécifique des plaquettes sanguines). Dans le but d'apporter des informations structurales concernant cette interaction et de façon à contribuer à élucider le rôle de CIB vis-à-vis du récepteur plaquettaire [alpha]IIb[bêta]3, nous avons étudié l'interaction in vitro entre un peptide correspondant à la partie cytoplasmique de la sous-unité [alpha]IIb : le peptide [alpha]IIb(Kexp. 989-Eexp. 1008) et le domaine C-terminal de CIB, celui là même capable de fixer le calcium. La RMN a été notre technique de choix pour étudier cette interaction au niveau moléculaire. L'obtention de l'un et l'autre des partenaires pur et enrichi en isotopes stables 15N et 13C s'est effectuée grâce à l'utilisation du domaine B1 de la protéine G de streptocoque en tant que protéine de fusion. Cette étape nous a permis dans un premier temps de définir les conditions d'expression, de purification et de solubilisation adéquates pour l'obtention de spectres RMN de qualité et exploitables pour chacune des molécules seules en solution, et d'en étudier les caractéristiques structurales et biochimiques. Dans un second temps, nous avons étudié l'une et l'autre des molécules dans leur interaction avec leur partenaire moléculaire. Nous avons tout d'abord constaté que l'interaction est caractérisée par une faible affinité
Ceci nous a notamment permis de montrer que sur le peptide correspondant au domaine cytoplasmique de [alpha]IIb, l'interaction implique des résidus situés dans une séquence juxta-membranaire conservée entre les sous-unités alpha des intégrines (GFFKR). Cette séquence est justement importante pour une interaction de nature électrostatique et hydrophobe avec la séquence conservée juxta-membranaire des sous-unités bêta (LLxxxHDR). Ainsi, si une interaction entre les domaines cytoplasmiques des intégrines [alpha] et [bêta] permet le maintien d'un récepteur inactif (récepteur de faible affinité pour un ligand extracellulaire), alors en interagissant avec cette séquence conservée juxta-membranaire de la sous-unité [alpha]IIb, il est probable que CIB soit un des facteurs intracellulaire susceptible de supprimer cette interaction et ainsi susceptible de provoquer l'activation du récepteur (conversion du récepteur de basse affinité vers un récepteur de haute affinité pour un ligand extracellulaire), ou bien de le maintenir dans une conformation active (haute affinité pour le ligand). Selon nos résultats, l'affinité entre le peptide [alpha]IIb(Kexp. 989-Eexp. 1008) et le domaine C-terminal de CIB est faible. Cette donnée associée aux résultats d'une autre équipe de recherche selon laquelle il existe une forte affinité entre un peptide plus long [alpha]IIb(Lexp. 983-Eexp. 1008) et CIB suggère que CIB occupe très certainement un rôle dans le maintien d'une intégrine [alpha]IIb[bêta]3 activée plutôt que dans l'activation proprement dite du récepteur
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4

Wang, Xue. "Predicting Protein Calcium Binding Sites." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/cs_diss/46.

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Анотація:
Calcium is one of the closely relevant metal ions that involves in enormous physicochemical activities in human body, including cell division and apoptosis, muscle contraction, neurotransmitter release, enzyme activation, and blood-clotting. Calcium fulfills its functions through the binding to different classes of calcium-binding proteins. To facilitate our understanding of the roles of calcium in biological systems, and to design novel metal-binding proteins with tailored binding capabilities, it is important to develop computation algorithms to predict calcium-binding sites in different classes of proteins. In literature, calcium-binding sites may be represented by either a spacial point, or the set of residues chelating calcium ion. A thorough statistical analysis of known calcium-binding proteins deposited in Protein Data Bank gives reference values of various parameters characterizing geometric and chemical features in calcium-binding sites including distances, angles, dihedral angles, the Hull property, coordination numbers, ligand types and formal charges. It also reveals clear differences between the well-known EF-hand calcium-binding motif and other calcium-binding motifs. Utilizing the above multiple geometric and chemical parameters in well-formed calcium binding sites, we developed MUG (MUltiple Geometries) program. MUG can re-identify the coordinates of the documented calcium ion and the set of ligand residues. Three previously published data sets were tested. They are comprised of, respectively, 19, 44 and 54 holo protein structures with 48, 92 and 91 documented calcium-binding sites. Defining a "correct hit" as a point within 3.5 angstrom to the documented calcium location, MUG has a sensitivity around 90% and selectivity around 80%. The set of ligand residues (calcium-binding pockets) were identified for 43, 66 and 63 documented calcium ion in these three data set respectively. In order to achieve true prediction, our program was then enhanced to predict calcium-binding pockets in apo (calcium-free) proteins. Our new program MUGSR accounts for the conformational changes involved in calcium-binding pockets before and after the binding of calcium ions. It is able to capture calcium binding pockets that may undergo local conformational changes or side chain torsional rotations, which is validated by referring back to the corresponding holo protein structure sharing more than 98% sequence similarity with the apo protein.
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5

Vosnidou, Nancy Carol Hoffman. "Computational analysis of cadherins : sequence analysis of dimerization properties and quantum caculations of calcium coordination characteristics /." free to MU campus, to others for purchase, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3060154.

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6

Bouissou, Camille. "Encapsulation of an integrin-binding protein into PLGA microspheres." Thesis, University of Bath, 2006. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432835.

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7

Walker, Simon W. "Studies on the intracellular calcium-binding protein calmodulin." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235957.

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8

Rönning, Sanne. "Selection of a calcium-dependent IgG1-binding protein domain." Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-417065.

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Анотація:
Standard purification processes in large scale antibody production are largely dependent on Protein A chromatography. Protein A binds specifically to many subclasses of IgG with high affinity. However, in order to elute the proteins, the pH needs to be lowered. Since lowering of the pH can be detrimental to some antibodies, a milder purification process is of great interest. A variant of Protein A, called ZCa, has previously been engineered to bind to IgG in a calcium-dependent manner. The antibody binds to ZCa when calcium is present and releases when calcium is removed. For the IgG1 subclass, the elution still requires a slight lowering of the pH, which is why there is room for improvement of the molecule. A phage display selection has been performed with the aim to obtain calcium-dependent IgG1 binders that are able to release the antibodies upon calcium depletion at neutral pH. In addition, an attempt on increasing the alkaline stability of the binders was made. Sequence analysis of the selection output showed almost no indications of increased alkaline stability. Instead, M13K07 helper phages were exposed to new selections for increased alkaline tolerance which might be useful in future phage display selections. Even though the binders selected for in this project did show some promising characteristics, none of them were able to elute upon calcium depletion at neutral pH as aimed for. However, one of the variants did show promising results during most of the performed characterizations. Most interestingly, the elution properties of this variant could indicate a higher calcium-dependence in the interaction with the target than that of ZCa, although further characterizations need to be performed in order to draw any conclusions about possible improvements of this protein domain.
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9

Kumar, Mohit. "Cardiac Myosin Binding Protein-C phosphorylation Regulates Calcium Homeostasis." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin159584822092564.

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10

Woodard-Grice, Alencia V. "Hyposialylation regulates [alpha]4[beta]1 integrin binding to VCAM-1." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2008. https://www.mhsl.uab.edu/dt/2009r/woodard.pdf.

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11

Keselowsky, Benjamin George. "Engineering surfaces to direct integrin binding and signaling to promote osteoblast differentiation." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/8092.

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Cell adhesion to proteins adsorbed onto implanted surfaces is particularly important to host responses in biomedical and tissue engineering applications. Biomaterial surface properties influence the type, quantity and functional presentation (activity) of proteins adsorbed upon contact with physiological fluids, and modulate subsequent cell response. Cell adhesion to extracellular matrix proteins (e.g. fibronectin) is primarily mediated by the integrin family of cell-surface receptors. Integrins not only anchor cells, supporting cell spreading and migration, but also trigger signals that regulate survival, proliferation and differentiation. A fundamental understanding of the adhesive interactions at the biomaterial interface is critical to the rational design of biomaterial surfaces. Using model surfaces of self-assembled monolayers of alkanethiols on gold presenting well-defined surface chemistries (CH3, OH, COOH, NH2), we investigated the effects of surface chemistry on osteoblastic differentiation. We report that surface chemistry effectively modulates fibronectin adsorption, integrin binding, focal adhesion assembly and signaling to direct the osteoblast cellular functions of adhesion strength, gene expression and matrix mineralization. Specifically, surfaces presenting OH and NH2 functionalities provide enhanced functional presentation of adsorbed fibronectin, promoting specificity of integrin binding as well as elevating focal adhesion assembly and signaling. Furthermore, the OH and NH2 surfaces supported elevated levels of osteoblast differentiation as evidenced by osteoblast-specific gene expression and matrix mineralization. These results contribute to the development of design principles for the engineering of surfaces that direct cell adhesion for biomedical and tissue engineering applications. In particular, the understanding provided by this analysis may be useful in the engineering of surface properties for bone tissue repair and regeneration.
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12

Ellis, April L. "Rational Design of Calcium Biosensors." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/chemistry_diss/25.

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Understanding the temporal and spatial changes in calcium concentration has been a difficult endeavor for many years due to the relatively small changes in calcium concentration during messenging events, the rapid changes upon physiological messenging, and the unavailability of fast, efficient, and sensitive sensors to detect calcium changes. In addition, the key factors in calcium binding have yet to be determined due to the metal-metal interactions, cooperativity, and conformational change involved in calcium binding to natural calcium-binding proteins. To overcome these obstacles and to engineer calcium sensors for in vivo studies of calcium signaling events, calcium binding sites have been engineered into Green Fluorescent Protein. The engineered binding sites demonstrate terbium binding affinity from 2-30 ƒÝM and calcium binding affinity from 50-100 ƒÝM. Site 177 demonstrates green fluorescence when expressed in mammalian cells and produces a response to calcium concentration changes when expressed in the cytosol. Addition of the cycle 3 mutations (M153T, V163A, F99S) to Site 177 allowed for increased brightness in the emission of the chromophore but still exhibited calcium response. The second generation Site 1 demonstrates fluorescence response to calcium concentration changes when expressed both in the cytosol and in the endoplasmic reticulum. Addition of M153T and V163A to Site 1 allowed for expression of fluorescent protein at 37 ¢XC in HeLa cells and at 30 ¢XC in bacteria. Site 1-M153T/V163A exhibits chromophore fluorescence response to calcium with a Kd of 100 ƒÝM and competition with Rhodamine-5N produced a calcium Kd of 107 ƒÝM. This designed sensor, Site 1-M153T/V163A is the first demonstration of a designed calcium binding GFP with calcium response measured both in vivo and in vitro.
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13

Davies, Michael Peter Alan. "Expression of the rat calcium-binding protein p9Ka in transgenic mice." Thesis, University of Liverpool, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.357240.

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14

Stewart, Terence John. "Molecular characterization of Sm20, a calcium binding protein of Schistosoma mansoni." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239659.

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15

Hou, Tien-tzu. "Role of intracellular calcium-binding protein parvalbumin in skeletal muscle function /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487676847116788.

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16

Castiblanco, Adriana P. "Expression and Purification of Engineered Calcium Binding Proteins." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/chemistry_theses/20.

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Previous studies in Dr. Yang’s laboratory have established a grafting, design, and subdomain approach in order to investigate the properties behind Ca2+-binding sites located in Ca2+-binding proteins by employing engineered proteins. These approaches have not only enabled us to isolate Ca2+-binding sites and obtain their Ca2+-binding affinities, but also to investigate conformational changes and cooperativity effects upon Ca2+ binding. The focus of my thesis pertains to optimizing the expression and purification of engineered proteins with tailored functions. Proteins were expressed in E. coli using different cell strains, vectors, temperatures, and inducer concentrations. After rigorous expression optimization procedures, proteins were further purified using chromatographic and/or refolding techniques. Expression and purification optimization of proteins is essential for further analyses, since the techniques used for these studies require high protein concentrations and purity. Evaluated proteins had yields between 5-70 mg/L and purities of 80-90% as confirmed by SDS-PAGE electrophoresis.
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17

Moes, Michèle. "Interaction of the cytoskeletal protein talin with the integrin beta3 subunit cytoplasmic tail: characterization of the talin rod IBS2 integrin binding site." Doctoral thesis, Universite Libre de Bruxelles, 2007. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210658.

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Talin is a multifunctional cytoskeletal protein that plays a critical role in linking the actin cytoskeleton to the integrin family of transmembrane cell adhesion receptors. Two distinct integrin binding sites have been identified in talin, one present in the globular head domain (IBS1) and involved in integrin activation, and a second (IBS2), that has been delineated to a 130 residue fragment of the talin rod domain, but whose functional role is still elusive (Tremuth et al.2004). The objective of the present study was to define the minimal structure of talin IBS2 and to investigate its functional role in the integrin-cytoskeleton connection.

In the first part of this study, we used a combination of three different experimental approaches to define the minimal structure of talin IBS2: 1) an in silico bioinformatics approach to analyse sequence conservation of talin IBS2, 2) an in vivo cell biology approach to study the subcellular localization of recombinant talin fragments covering IBS2 in CHOáIIbâ3 cells, and 3) an in vitro biochemical approach consisting in protein overlay, pull down and Surface Plasmon Resonance (SPR) assays, to study the direct interaction between talin IBS2 and the integrin â3 subunit. We delineated IBS2 to a single amphipathic á-helical repeat of 23 residues within the talin rod domain. We further provided evidence that a two amino acid mutation(L2094I2095/AA) was sufficient to inactivate the IBS2 site, due to a disruption of the á helix structure, as demonstrated by infrared spectroscopy. In addition, we identified 2 lysine residues (K2085, K2089) exposed on the solvent face of á helix 50, which are directly involved in the talin IBS2-integrin interaction.

In the second part of this study, we investigated the functional role of talin IBS2 in spreading defective talin (-/-) cells and showed that in contrast to full-length wild type talin, an IBS2 LI/AA mutant talin was unable to fully rescue the spread phenotype of these cells. These results provide the first direct evidence that IBS2 in the talin rod is essential to link integrins to the actin cytoskeleton.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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18

Allhouse, Leanne Dawn. "Characterisation of troponin C, the calcium binding protein of barnacle striated muscle." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312246.

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19

Baker, Christian. "Developmental challenge and GABAergic neuronal abnormalities : their relevance to schizophrenia." Thesis, University of Sheffield, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274951.

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20

Williams, James M. A. "Studies on the transport of calcium across the dually perfused lobule of the human term placenta." Thesis, University of Aberdeen, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387461.

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Movements of calcium (Ca) across the maternal and fetal aspects of the human placenta were investigated using the isolated placental lobule dually perfused in vitro. Tissues uptakes and releases of calcium were measured and the effects on calcium movements by calcium-protein binding in the perfusion fluids, (associated with extracellular pathways and non-uniform perfusion), evaluated. The effects of ouabain, dinitrophenol (DNP), and cooling on calcium movements were measured and compared to movements of Na+ and K+. These indicated the presence of active transport of calcium but no evidence was obtained for Ca2+/Na+ exchange. Cyclic adenosine 3', 5' -monophosphate (cAMP) levels in dually perfused tissue were measured following microwave fixation. This technique was used to measure changes in tissue cAMP production following exposure to forskolin, 3-iso-butyl-l-ethyl-xanthine (IBMX), and various fragments of both bovine parathyroid hormone (bPTH) and human parathyroid hormone-related peptide (hPTHrP). Rises in cAMP were produced by exposure to bPTH(1-34) but not hPTHrP(1-34), hPTHrP(67-86) or hPTHrP (107-138). It is concluded that calcium is actively transported across the placenta but there is no major contribution via a Ca2+/Na+ exchanger. The patterns of calcium uptake as a function of perfusate calcium concentration support the evidence of other workers that extracellular pathways are present in the syncytiotrophoblast. A significant amount of passive movement of calcium may therefore take place across the perfused placenta. The 1 to 34 region of the PTH molecule stimulates the production of cAMP by the trophoblast, but there is no indication that this has any effect on transplacental Ca transport.
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21

Jones, Lisa Michelle. "Using Protein Design to Understand the Role of Electrostatic Interactions on Calcium Binding Affinity and Molecular Recognition." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/chemistry_diss/16.

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Calcium regulates many biological processes through interaction with proteins with different conformational, dynamic, and metal binding properties. Previous studies have shown that the electrostatic environment plays a key role in calcium binding affinity. In this research, we aim to dissect the contribution of the electrostatic environment to calcium binding affinity using protein design. Many natural calcium binding proteins undergo large conformational changes upon calcium binding which hampers the study of these proteins. In addition, cooperativity between multiple calcium binding sites makes it difficult to study site-specific binding affinity. The design of a single calcium binding site into a host system eliminates the difficulties that occur in the study of calcium binding affinity. Using a computer algorithm we have rationally designed several calcium binding sites with a pentagonal bipyramidal geometry in the non-calcium dependent cell adhesion protein CD2 (CD2-D1) to better investigate the key factors that affect calcium binding affinity. The first generation proteins are all in varying electrostatic environments. The conformational and metal binding properties of each of these designed proteins were analyzed. The second generation designed protein, CD2.6D79, was designed based on criteria learned from the first generation proteins. This protein contains a novel calcium binding site with ligands all from the â-strands of the non-calcium dependent cell adhesion protein CD2. The resulting protein maintains native secondary and tertiary packing and folding properties. In addition to its selectivity for calcium over other mono and divalent metal ions, it displays strong metal binding affinities for calcium and its analogues terbium and lanthanum. Furthermore, our designed protein binds CD48, the ligand binding partner of CD2, with an affinity three-fold stronger than CD2. The electrostatic potential of the calcium binding site was modified through mutation to facilitate the study of the effect of electrostatic interactions on calcium binding affinity. Several charge distribution mutants display varying metal binding affinities based on their charge, distance to the calcium binding site, and protein stability. This study will provide insight into the key site factors that control calcium binding affinity and calcium dependent biological function.
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22

Chen, Shan. "Histidine-Rich Ca Binding Protein and Cardiac Functions." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1242973363.

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23

Skene, Robert J. "Crystallographic studies of calcium-binding proteins, aeromonas salmonicida surface array protein and calmodulin." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ64978.pdf.

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24

Palmer, Claire Louise. "Biochemical investigation into the function of hippocalcin, a neurone-specific calcium binding protein." Thesis, University of Bristol, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271880.

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25

Swan, David Gerard. "The structural gene for a calcium-binding protein from Saccharopolyspora erthyraea (Streptomyces erthyreus)." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316010.

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26

Birkholz, Tyler M. "Exploring the Role of Calcium-Binding Protein Calreticulin in the Mouse Suprachiasmatic Nucleus." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1562689789471245.

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27

Tessarolo, Diane. "Cytoskeletal localization and function of calcium-binding protein 1 (CBP1) during Dictyostelium discoideum development." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0021/MQ59208.pdf.

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28

Gumpel, Nicola Jane. "Characterisation of uroporphyrinogen III synthase and a novel calcium binding protein from Euglena gracilis." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386737.

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29

Rajamanoharan, Dayani. "Investigating calcium binding protein 7 (CaBP7), phosphoinositide signalling and lysosomes during mammalian cell mitosis." Thesis, University of Liverpool, 2015. http://livrepository.liverpool.ac.uk/2044661/.

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Calcium binding proteins (CaBPs) are a subfamily of the calmodulin related superfamily of EF hand containing proteins. CaBPs can be further divided into two subgroups (CaBPs 1-5 and CaBP7 and 8) due to differing cation binding properties and because CaBP7 and 8 have a distinct trans- membrane domain at the C-terminal that is essential for determining their subcellular location. CaBP7 and 8 have been shown to interact with Golgi resident Phosphatidylinositol 4-Kinase-IIIbeta (PI4KIIIβ) and to be involved in calcium (Ca2+) regulated Golgi to plasma membrane trafficking pathway. At resting Ca2+ levels CaBP7 and 8 interact with PI4KIIIβ and inhibit its enzymatic function, to prevent phosphatidylinositol 4-phosphate (PI4P) synthesis and vesicular trafficking. At high Ca2+ levels another Golgi resident Ca2+-binding protein, neuronal calcium sensor-1 (NCS-1), displaces CaBP7 and 8 from PI4KIIIβ, stimulating PI4P production and thereby coupling local Ca2+ signals to vesicular transport. In addition to this documented trafficking function, a high- throughput RNAi screen identified CaBP7 as an essential factor for successful completion of cytokinesis in HeLa cells. Mitotic cell division is a fundamental biological process required for normal cellular growth, development and aging. Mitotic failure can lead to a state of aneuploidy, which is an accepted driver of cellular transformation and tumorigenesis. Therefore, this thesis specifically focused on CaBP7 with an aim to understand its unique role during mammalian cell mitosis. When the subcellular localisation of CaBP7 was examined it was found to be present on both the Golgi complex and, unexpectedly, lysosomes. A recent study identified a previously uncharacterised lysosomal pool of PI4KIIIβ, ! i! cellular depletion of which disrupted lysosome trafficking and ultimately led to distinctive lysosomal clustering. In an effort to connect these findings, analyses were designed to reveal whether CaBP7 was involved in regulation lysosomal PI4KIIIβ. CaBP7 overexpression (inhibition of PI4KIIIβ) increased clustering of lysosomes in a similar manner to that observed on cellular depletion of PI4KIIIβ. This result provides evidence to suggest a role for CaBP7 in lysosomal PI4KIIIβ regulation and lysosome trafficking, which will require further research to fully delineate. In order to further understand CaBP7 involvement in mitosis, CaBP7 was depleted from cells using shRNAi, which resulted in a 3-fold increase in binucleate cells compared to control cells. Binucleate cells form as a direct consequence of cytokinesis failure implying a functional requirement for CaBP7 during this process. This data replicated findings from the previous large scale RNAi screen and was extended upon significantly in this study through an analysis of a range of PI4KIIIβ effectors and their influence on mitosis. The same binucleate phenotype was observed with PI4KIIIβ overexpression suggesting a role for CaBP7 in regulating PI4KIIIβ during cytokinesis. Localisation studies revealed that CaBP7, PI4KIIIβ and lysosomes re-distributed together extensively during mitosis implying a link between all three in this process. In particular, at cytokinesis, all three components were localised in discrete clumps flanking either side of the nucleus. Intriguingly this marked re-distribution was lost upon CaBP7 depletion, possibly revealing a mechanistic link to cytokinesis failure. Collectively, data acquired regarding CaBP7, PI4KIIIβ and lysosomes inferred a role for lysosome positioning during mitosis and to test this ! ii! hypothesis experiments were designed to examine a requirement for specific lysosomal activities during cytokinesis. Lysosomes have emerged as Ca2+ signalling platforms and this function was assessed using novel genetically encoded Ca2+ sensors targeted specifically to these organelles. No Ca2+ signals originating from lysosomes during mitotic cell division were detected in these analyses. The other known functions of lysosomes were also examined in these studies. Inhibition of lysosomal catabolism failed to influence mitosis however disruption of lysosomal membrane fusion with the agents GPN and vacuolin-1 induced a significant increase of binucleate cell numbers. Collectively these functional assays suggest a potential requirement for lysosomal membrane fusion during cytokinesis, which would be consistent with a documented function for endosomes during this process. This thesis provides new insights into the role of a Ca2+ binding proteins, phosphoinositide signalling and, uniquely, lysosomal compartments, during mammalian cell mitosis. It describes an outline for a potentially new regulatory input into mitosis and provides a platform for future detailed examinations of the mechanistic links between CaBP7, lysosomes, lysosomal PI4KIIIβ activity and PI4P levels during normal cytokinesis in mammalian cells.
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30

Chen, Yanyi. "Dissecting Key Determinants for Calcium and Calmodulin Regulation of GAP Junction and Viral Protein." Digital Archive @ GSU, 2012. http://digitalarchive.gsu.edu/chemistry_diss/64.

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Calcium and calmodulin are implicated in mediating the Ca2+-dependent regulation of gap junctions that are essential for the intercellular transmission of molecules such as nutrients, metabolites, metal ions and signal messengers (< 1000 Da) through its specialized cell membrane channels and communication to extracellular environment. To understand the key determinants for calcium and calmodulin regulation of gap junction, in this study, we identified a calmodulin binding domain in the second half of the intracellular loop of Cxonnexin50 (the major gap junction protein found in an eye lens) using peptide fragments that encompass predicted CaM binding sites and various biophysical methods. Our study provides the first direct evidence that CaM binds to a specific region of the ubiquitous gap junction protein Cx50 in a Ca2+-dependent manner. Furthermore, two novel CaM binding regions in cytosolic loop and C-termini of Connexin43 (the most ubiquitous connexin) have been shown to interact with CaM with different binding modes in the presence of Ca2+ using high resolution NMR. Our results also elucidate the molecular determinants of regulation of gap junction by multiple CaM targeting regions and provide insight into the molecular basis of gap junction gating mechanism and the binding of CaM to the cytoslic region Cx43-3p as the major regulation site. Upon response to the cytosolic calcium increase, CaM binds to the cytosolic loop to result in the conformational change of gap junction and close the channel. It is possible for CaM to use an adjacent region as an anchor close to the regulation site to allow for fast response. Since a large number of residues in the Cxs mutated in human diseases reside at the highly identified CaM binding sites in Cxs, our studies provide insights into define the critical cellular changes and molecular mechanisms contributing to human disease pathogenesis as part of an integrated molecular model for the calcium regulation of GJs. In addition, we have applied the grafting approach to probe the metal binding capability of predicted EF-hand motifs within the streptococcal hemoprotein receptor (Shr) of Streptococcus pyrogenes as well as the nonstructural protein 1 (nsP1) of Sindbis virus and Poxvirus. This fast and robust method allows us to analyze putative EF-hand proteins at genome-wide scale and to further visualize the evolutionary scenario of the EF-hand protein family. Further, mass spectrometry has also been applied to probe modification of proteins such as CaM labeling by florescence dye and 7E15 by PEG.
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31

Agah, Sayeh. "Parvalbumin stability and calcium affinity : the impact of the n-terminal domain /." Free to MU Campus, others may purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?3164486.

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32

Eastlake, Jane Louise. "Calmodulin from the eucestoda Hymenolepis diminuta : an investigative study." Thesis, University of Bath, 1994. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.387426.

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33

Clark, Ruti H. "A model system for investigating biomineralization : elucidating protein G/calcium oxalate monohydrate interactions /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/8067.

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34

Gagné, Stéphane M. "Structures, dynamics and energetics of troponin C, the tale of a muscular calcium-binding protein." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0023/NQ39528.pdf.

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35

Schacht, Teresa [Verfasser]. "Neuronal calcium-binding protein 2 (NECAB2): Charakterisierung eines striatalen Ca 2+ -bindenden Proteins / Teresa Schacht." Mainz : Universitätsbibliothek Mainz, 2017. http://d-nb.info/1141937689/34.

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36

Kim, Kristin. "Characterization of calcium binding protein 1 (CaBP1/CD) expression and localization in the mouse brain." Thesis, University of Iowa, 2013. https://ir.uiowa.edu/etd/2545.

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Ca2+-binding proteins (CaBP) alter Ca2+ signals, triggering cellular processes such as gene transcription regulation in neurons. CaBP1/CD is a calmodulin (CaM)-like Ca2+ binding protein that may regulate neuronal functions through interactions with effectors such as voltage-gated Ca2+ (Cav) channels and inositol trisphosphate receptors (InsP3Rs). To gain insight into the potential cellular functions of CaBP1/CD, we analyzed the expression and localization of CaBP1/CD variants in mouse brain. Of the three CaBP1/CD splice variants that have been characterized (CaBP1-S, CaBP1-L, and caldendrin (CD)), CD was the major variant expressed in mouse brain by western blot and quantitative polymerase chain reaction. These results reflected the expression of CaBP1/CD since they were not reproduced in mice with targeted disruption of the gene encoding CaBP1/CD (CaBP1 knock-out). By immunoperoxidase labeling, CaBP1/CD was localized in multiple cell-types including pyramidal cells in the cerebral cortex and hippocampal CA3 neurons and inhibitory neurons in the cerebellum. In the cerebellum, CaBP1/CD was not detected in Purkinje neurons but strongly colocalized with voltage-sensitive Shaker-type potassium channel, Kv1.2, in the pinceau formation formed between basket cells and the Purkinje cell axon initial segment. We conclude that CaBP1/CD is expressed in a subset of principal neurons where it may regulate Ca2+ signaling and neuronal excitability.
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37

Jones, Lisa Michelle. "Using protein design to understand the role of electrostatic interactions on calcium binding affinity and molecular recognition." unrestricted, 2006. http://etd.gsu.edu/theses/available/etd-07282006-143357/.

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Thesis (Ph.D.)--Georgia State University, 2006.
Title from file title page. Jenny J. Yang, committee chair; Alfons Baumstark, Giovanni Gadda, committee members. Electronic text (405 p. : ill. (some col.)) : digital, PDF file. Description based on contents viewed Aug. 20, 2008. Includes bibliographical references (p. 380-405).
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38

Prichard, Lisa. "The role of the IQ motif, a protein kinase C and calmodulin regulatory domain, in neuroplasticity, RNA processing, and RNA metabolism /." Thesis, Connect to this title online; UW restricted, 1998. http://hdl.handle.net/1773/6302.

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39

Dharamsi, Akil G. "Studies on the function of Calcium Binding Protein 1 (CBP1) during the development of Dictyostelium discoideum." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ27345.pdf.

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40

Casey, Diane M. "DC3, a Calcium-Binding Protein Important for Assembly of the Chlamydomonas Outer Dynein Arm: a Dissertation." eScholarship@UMMS, 2005. http://escholarship.umassmed.edu/gsbs_diss/156.

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The outer dynein arm-docking complex (ODA-DC) specifies the outer dynein arm-binding site on the flagellar axoneme. The ODA-DC of Chlamydomonas contains equimolar amounts of three proteins termed DC1, DC2, and DC3 (Takada et al., 2002). DC1 and DC2 are predicted to be coiled-coil proteins, and are encoded by ODA3 and ODA1, respectively (Koutoulis et al., 1997; Takada et al., 2002). Prior to this work, nothing was known about DC3. To fully understand the function(s) of the ODA-DC, a detailed analysis of each of its component parts is necessary. To that end, this dissertation describes the characterization of the smallest subunit, DC3. In Chapter II, I report the isolation and sequencing of genomic and full-length cDNA clones encoding DC3. The sequence predicts a 21,341 D protein with four EF hands that is a member of the CTER (Calmodulin, Troponin C, Essential and Regulatory myosin light chains) group and is most closely related to a predicted protein from Plasmodium. The DC3 gene, termed ODA14, is intronless. Chlamydomonas mutants that lack DC3 exhibit slow, jerky swimming due to loss of some but not all, outer dynein arms. Some outer doublet microtubules without arms had a "partial" docking complex, indicating that DC1 and DC2 can assemble in the absence of DC3. In contrast, DC3 cannot assemble in the absence of DC1 or DC2. Transformation of a DC3-deletion strain with the wild-type DC3 gene rescued both the motility phenotype and the structural defect, whereas a mutated DC3 gene was incompetent to rescue. The results indicate that DC3 is important for both outer arm and ODA-DC assembly. As mentioned above, DC3 has four EF-hands: two fit the consensus pattern for calcium binding and one contains two cysteine residues within its binding loop. To determine if the consensus EF-hands are functional, I purified bacterially expressed wild-type DC3 and analyzed its calcium-binding potential in the presence and absence of DTT and Mg2+. As reported in Chapter III, the protein bound one calcium ion with an affinity (Kd) of ~1 x 10-5 M. Calcium binding was observed only in the presence of DTT and thus is redox sensitive. DC3 also bound Mg2+ at physiological concentrations, but with a much lower affinity. Changing the essential glutamate to glutamine in both EF-hands eliminated the calcium-binding activity of the bacterially expressed protein. To investigate the role of the EF hands in vivo, I transformed the modified DC3 gene into a Chlamydomonas insertional mutant lacking DC3. The transformed strain swam normally, assembled a normal number of outer arms, and had a normal photoshock response, indicating that the E to Q mutations did not affect ODA-DC assembly, outer arm assembly, or Ca2+-mediated outer arm activity. Thus, DC3 is a true calcium-binding protein, but the function of this activity remains obscure. In Chapter IV, I report the initial characterization of a DC3 insertional mutant having a phenotype intermediate between that of the DC3-deletion strain and wild type. Furthermore, I suggest future experiments that may help elucidate the specific role of DC3 in outer arm assembly and ODA-DC function. Lastly, I speculate that the ODA-DC may play a role in flagellar regeneration.
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41

Ripley, Scott James. "Biochemical characterisation and subcellular localisation of the ARP : a novel calcium-binding protein from Euglena gracilis." Thesis, University of Cambridge, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627242.

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42

Wang, Lianyong. "A calcium-binding protein CAS regulates the CO2-concentrating mechanism in the green alga Chlamydomonas reinhardtii." Kyoto University, 2017. http://hdl.handle.net/2433/218025.

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43

Casey, Diane M. "DC3, a Calcium-Binding Protein Important for Assembly of the Chlamydomonas Outer Dynein Arm: a Dissertation." eScholarship@UMMS, 2003. https://escholarship.umassmed.edu/gsbs_diss/156.

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Анотація:
The outer dynein arm-docking complex (ODA-DC) specifies the outer dynein arm-binding site on the flagellar axoneme. The ODA-DC of Chlamydomonas contains equimolar amounts of three proteins termed DC1, DC2, and DC3 (Takada et al., 2002). DC1 and DC2 are predicted to be coiled-coil proteins, and are encoded by ODA3 and ODA1, respectively (Koutoulis et al., 1997; Takada et al., 2002). Prior to this work, nothing was known about DC3. To fully understand the function(s) of the ODA-DC, a detailed analysis of each of its component parts is necessary. To that end, this dissertation describes the characterization of the smallest subunit, DC3. In Chapter II, I report the isolation and sequencing of genomic and full-length cDNA clones encoding DC3. The sequence predicts a 21,341 D protein with four EF hands that is a member of the CTER (Calmodulin, Troponin C, Essential and Regulatory myosin light chains) group and is most closely related to a predicted protein from Plasmodium. The DC3 gene, termed ODA14, is intronless. Chlamydomonas mutants that lack DC3 exhibit slow, jerky swimming due to loss of some but not all, outer dynein arms. Some outer doublet microtubules without arms had a "partial" docking complex, indicating that DC1 and DC2 can assemble in the absence of DC3. In contrast, DC3 cannot assemble in the absence of DC1 or DC2. Transformation of a DC3-deletion strain with the wild-type DC3 gene rescued both the motility phenotype and the structural defect, whereas a mutated DC3 gene was incompetent to rescue. The results indicate that DC3 is important for both outer arm and ODA-DC assembly. As mentioned above, DC3 has four EF-hands: two fit the consensus pattern for calcium binding and one contains two cysteine residues within its binding loop. To determine if the consensus EF-hands are functional, I purified bacterially expressed wild-type DC3 and analyzed its calcium-binding potential in the presence and absence of DTT and Mg2+. As reported in Chapter III, the protein bound one calcium ion with an affinity (Kd) of ~1 x 10-5 M. Calcium binding was observed only in the presence of DTT and thus is redox sensitive. DC3 also bound Mg2+ at physiological concentrations, but with a much lower affinity. Changing the essential glutamate to glutamine in both EF-hands eliminated the calcium-binding activity of the bacterially expressed protein. To investigate the role of the EF hands in vivo, I transformed the modified DC3 gene into a Chlamydomonas insertional mutant lacking DC3. The transformed strain swam normally, assembled a normal number of outer arms, and had a normal photoshock response, indicating that the E to Q mutations did not affect ODA-DC assembly, outer arm assembly, or Ca2+-mediated outer arm activity. Thus, DC3 is a true calcium-binding protein, but the function of this activity remains obscure. In Chapter IV, I report the initial characterization of a DC3 insertional mutant having a phenotype intermediate between that of the DC3-deletion strain and wild type. Furthermore, I suggest future experiments that may help elucidate the specific role of DC3 in outer arm assembly and ODA-DC function. Lastly, I speculate that the ODA-DC may play a role in flagellar regeneration.
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44

Tatsumi, Keiji. "Expression of calcium binding protein D-9k messenger RNA in the mouse uterine endometrium during implantation." Kyoto University, 1999. http://hdl.handle.net/2433/181740.

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45

Connors, Wendy Lee. "Sequential injection analysis for the investigation of biomolecular interactions /." Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/8481.

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46

Banjo, Taiwo Abayomi. "Acanthamoeba mannose-binding protein : structural and functional characterisation of a therapeutic target for Acanthamoeba keratitis." Thesis, University of Leicester, 2018. http://hdl.handle.net/2381/42327.

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Acanthamoeba mannose-binding protein (AcMBP) is a virulence factor of the free-living amoeba, Acanthamoeba castellanii. It is crucial for the development of Acanthamoeba keratitis (AK), a corneal infection that often causes blindness. AK is associated with contact lens use and contaminated water sources. Therapeutic unresponsiveness is attributed to similarities in the biological processes that Acanthamoeba shares with humans and its ability to form drug-resistant cysts. I aimed to characterise AcMBP as a basis for developing future drugs against Acanthamoeba. To start with, I carried out morphological studies on the two well-known life stages of Acanthamoeba and characterised a third stage: the protocysts. Mature cysts and protocysts could not interconvert directly, but always excysted to trophozoites. This is important because Acanthamoeba can potentially be trapped as protocysts, which are likely to be more susceptible to drugs. I also studied Acanthamoeba adhesion towards various surfaces and cytopathic activities towards cells (including human corneal epithelial cells). Whilst AcMBP was important for adhesion, it is not the only receptor involved. To gain structure/function information, I expressed the extracellular portion of AcMBP and three truncated fragments. AcMBP is a Ca2+-dependent lectin (~100 kDa) that binds to mannose. Ca2+ is essential for lectin activity and stability. The extracellular fragment is monomeric, indicating that trimerisation, shown previously, depends on the membrane-spanning and/or intracellular regions. Bioinformatics revealed that lectin activity is almost certainly located in a DUF 4114 domain (~10 kDa, DUF: domain of unknown function). N-terminal fragments, including the DUF4114 domain did not bind to mannose-Sepharose, suggesting that part of the cysteine-rich domain is also important. AcMBP bound to a variety of mammalian glycans so may have more than one lectin activity. Although attempts to crystallise AcMBP were unsuccessful, future structural analysis will be useful for defining the domains and determining how it binds to mannose.
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47

Xie, Yi. "Metastasis and angiogenesis in neuroblastoma involvement of visinin like protein-1 and dendritic cell /." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B38588250.

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48

Xie, Yi, and 謝弋. "Metastasis and angiogenesis in neuroblastoma: involvement of visinin like protein-1 and dendritic cell." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B38588250.

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49

Lee, Hsiau-Wei. "Determining The Site Specific Metal Binding and Structural Properties of EF-Hand Protein Using Grafting Approach." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/chemistry_diss/26.

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Calmodulin is an essential EF-hand protein with a helix-loop-helix calcium binding motif. Understanding Ca(II) dependent activation of calmodulin and other EF-hand proteins is limited by Ca(II)-induced conformational change, multiple and cooperative binding of Ca(II) ions, and interactions between the paired EF-hand motifs. The goal of this research project is to probe key determinants for calcium binding properties and pairing interactions at the site specific level using a grafting approach and high resolution NMR. An individual Ca(II) binding site of the EF-hand motifs of calmodulin was grafted into a non-calcium dependent protein, CD2, to bypass limitations associated with natural EF-hand proteins and peptide fragments. Using high resolution NMR, we have shown that the grafted EF-loop III of calmodulin in the host protein retains its native conformation with a strong loop and β-conformation preference. Grafted ligand residues in the engineered protein are directly involved in binding of Ca(II) and La(III). The NMR studies support our hypothesis that both ligand arrangement and dynamic properties play essential role in tuning Ca(II) binding affinities. Using pulse-field diffusion NMR and protein engineering, we further demonstrated that grafted EF- loop remains as a monomer. Although the EF-loop with flanking helices dimerizes in the presence of Ca(II). Additionally, removal of conserved hydrophobic residues at the flanking helices of the EF-hand motif leads to be monomer in the absence and presence of metal ions. Our results suggest that conserved hydrophobic residues are essential for the pair-paired interaction in the coupled EF-hand protein. We have shown that our developed grafting approach can be applied to probe intrinsic Ca(II) binding affinities of different Ca(II) binding sites.
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50

Chen, Xi Lin. "Régulation de l'apoptose des lymphocytes T par GIMAP5 (GTPase of Immune Associated Nucleotide Binding Protein 5)." Thèse, Université de Sherbrooke, 2015. http://hdl.handle.net/11143/7593.

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Abstract : Long-term survival of T lymphocytes in a quiescent state is essential to maintain their cell numbers in secondary lymphoid organs. Interaction of the T cell antigen receptor (TCR) with self-peptide/MHC synergizes with IL-7-induced anti-apoptotic signals to promote T cell survival. These extrinsic stimuli are also implicated in T cell metabolism and survival by regulating several signaling pathways including the phosphatidyl-inositol-3 kinase (PI3K)/Akt pathway. In mice and in rats, loss of functional GTPase of the immune associated nucleotide binding protein 5 (GIMAP5) causes peripheral T lymphopenia due to spontaneous death of T cells. The underlying mechanisms responsible for the pro-survival function of GIMAP5 in T lymphocytes remain largely unknown. Previous work from my laboratory has shown that T cells from GIMAP5-deficient rats show reduced influx of calcium (Ca[superscript 2+]) from the extracellular milieu following stimulation of the TCR complex. In this thesis, I characterized the mechanism by which GIMAP5 regulates Ca[superscript 2+] homeostasis, and elucidated the signaling pathways modulated by GIMAP5 to facilitate the survival of T cells. Firstly, I investigated if GIMAP5 prevents apoptotic death of T lymphocytes by affecting the Ca[superscript 2+] buffering capacity of mitochondria, which is required for sustained Ca[superscript 2+] influx via the plasma membrane channels. I observed that mitochondrial Ca[superscript 2+] accumulation following capacitative Ca[superscript 2+] entry is defective in T cells from Gimap5 deficient rats. Disruption of microtubules, but not the actin cytoskeleton, abrogated Ca[superscript 2+] sequestration by mitochondria in T cells from control but not Gimap5 deficient mice. Similarly, mice lacking functional GIMAP5 displayed defective T cell development and Ca[superscript 2+] influx. Furthermore, I observed that the proximal signaling events following TCR stimulation was reduced and was accompanied by defective proliferation in T cells from Gimap5 deficient mice. Additionally, IL-7-induced STAT5 phosphorylation was decreased in CD4[superscript +] T cells from Gimap5 deficient mice. I also showed that loss of functional Gimap5 results in increased basal activation of mammalian target of rapamycin (mTOR), independent of protein phosphatase 2A (PP2A) or AMP-activated protein kinase (AMPK). Instead, the constitutive activation the PI3K pathway contributed to the spontaneous high mTOR activation. Collectively, my observations suggest that the pro-survival function of GIMAP5 in T-lymphocytes may be linked to the regulation of diverse signaling pathways in a context dependent manner. GIMAP5 also facilitates microtubule-dependent mitochondrial buffering of Ca[superscript 2+] following capacitative entry. GIMAP5 is required to integrate the survival signals generated following activation through TCR and IL-7R.
Résumé : La survie à long terme des lymphocytes T en état de repos est essentielle pour maintenir leurs nombres dans les organes lymphoïdes secondaires. Le récepteur antigénique des cellules T (TCR) en contact avec les peptides du soi / CMH et en synergie avec l'IL-7 induit des signaux anti-apoptotiques pour favoriser la survie des cellules T. Ces stimuli extrinsèques sont également impliqués dans le métabolisme et la survie des cellules T grâce à la régulation de plusieurs voies de signalisation dont la voie phosphatidyl-inositol-3 kinase (PI3K) /AKT. Chez la souris et chez le rat, la perte de l’activité de GIMAP5 (GTPase of Immune Associated Nucleotide Binding Protein 5), provoque une lymphopénie T périphérique en raison de la mort spontanée des cellules T. Le mécanisme sous-jacent responsable de la fonction de survie de GIMAP5 dans les lymphocytes T reste largement inconnu. Nous avons observé que les cellules de rats déficients en GIMAP5, après stimulation par complexe TCR, montrent un afflux de calcium (Ca[indice supérieur 2+]) réduit provenant du milieu extracellulaire. Dans cette thèse, J’ai caractérisé le mécanisme d’action de GIMAP5 dans la régulation de l'homéostasie du Ca[indice supérieur 2+], ainsi que les voies de signalisation modulées par GIMAP5 pour faciliter la survie des cellules T. Tout d'abord, j’ai étudié si GIMAP5 empêche l’apoptose des lymphocytes T en affectant la capacité des mitochondries à réguler la concentration du Ca[indice supérieur 2+], ce qui est nécessaire pour soutenir l’influx de Ca[indice supérieur 2+]. J’ai trouvé que l’accumulation du Ca[indice supérieur 2+] mitochondrial après l’entrée capacitive de Ca[indice supérieur 2+] est défectueuse dans les cellules T de rat déficientes en Gimap5. La disruption des microtubules, mais pas du cytosquelette d'actine, abroge la séquestration du Ca[indice supérieur 2+] mitochondrial dans les cellules T primaires de rat, mais pas dans les cellules T déficientes en Gimap5. J’ai observé que les cellules T provenant de souris déficientes en Gimap5 démontrent une diminution de l’entrée de Ca[indice supérieur 2+]. De plus, la prolifération des cellules T déficientes en Gimap5 est diminuée suite à la stimulation du TCR. En outre, la phosphorylation de STAT5 induit par l'IL-7 est diminuée dans les cellules T CD4[indice supérieur +] de souris déficientes en Gimap5. Également, la perte de Gimap5 aboutit à une activation accrue de la cible mammalienne de la rapamycine (mTOR), indépendamment de la protéine phosphatase 2A (PP2A) ou de la protéine kinase activée par l'AMP (AMPK). Au lieu de cela, l'activation constitutive de la voie PI3K contribue à une forte activation spontanée de mTOR. Collectivement, la fonction de survie de GIMAP5 dans les lymphocytes T peut être liée à la régulation de différentes voies de signalisation. GIMAP5 facilite la fonction, microtubule dépendant, des mitochondries dans leurs actions de régulation du Ca[indice supérieur 2+] après l’entrée capacitive de Ca[indice supérieur 2+]. GIMAP5 est nécessaire pour intégrer les signaux de survie produits suite à l'activation du TCR et de l’IL-7R, qui pourrait être associée à la régulation de l'activité PI3K / AKT / mTOR.
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До бібліографії